The present invention relates to an in-line-connector type of fluid hammer prevention device connected in series incorporated in a fluid channel such as a cold/hot water supply system or a fluid apparatus. More particularly, the present invention relates to an in-line fluid hammer prevention device capable of maintaining the pressure energy conversion efficiency for a long period of time by increasing the fluid sealing tightness of an elastic cushion by means of an elastic cylindrical diaphragm.
There have been several types of fluid hammer prevention device (arrestor) in conventional and popular style, for example known as xe2x80x9cwater hammer arrestor,xe2x80x9d which effectively reduce the phenomenon of fluid hammer occurring in a fluid channel such as a cold-hot water supply system or inside a fluid apparatus. The conventional fluid hammer prevention device may be roughly classified into two types, that is, an branch-off type connected at any intermediate position of the fluid channel to introduce the fluid branched from the main channel, and an in-line type in a shape of connector connected in series in a fluid channel such as a water pipe.
In particular, as referred to the Official Gazette of Japanese Patent No. 2908998, there are several products currently available in the market as xe2x80x9cwater hammer arrestorxe2x80x9d having excellent pressure energy fluctuation absorption performance. According to the water hammer prevention device (arrestor) of Japanese Patent No. 2908998, an orifice is placed at the position opposite to a diaphragm and cushion material, xe2x80x9csyntactic foamxe2x80x9d (or may be called as xe2x80x9csynthetic foamxe2x80x9d) made from the mixture of elastic micro balloon fillers and silicone resin is used as the cushion material, and a two-stage orifice is provided. The conventional branch-off type of fluid hammer prevention device, however, is protruding in the perpendicular direction from the pipe, thus having the problem of poor appearance and design, and of requirement of wider installation space and additional branch-off parts. Consequently, the current branch-off type water hammer arrestors have the problem of being difficult to cope with the demand of down-sizing and cost-reduction of cold/hot water supply system and fluid apparatus.
As the rising of concern about water hammer, the branch-off type of products discussed above have become widely used, and currently the in-line type connected in series in a piping system is drawing attention of many users as the fluid hammer prevention device which may be attached to the pipe by using the minimum space. There have already been disclosed several examples of this in-line type of fluid hammer prevention device as illustrated FIGS. 17(A)-(D), i.e. Japanese Unexamined Patent Publication No. Hei 3-186691, Japanese Unexamined Patent Publication No. Hei 2-253099, Japanese Unexamined Patent Publication No. Hei 6-147391 and Japanese Unexamined Utility Model Publication No. Hei 7-28296.
With reference to the Official Gazette of Japanese Unexamined Patent Publication No. Hei 3-186691, the fluid hammer prevention device as disclosed in FIG. 17(A) shows an embodiment, wherein, a cushion material 7 is fixed on and covers the inner peripheral wall of a connector 8 connected to the pipe at an intermediate point of a standpipe 3 (preferably in the vicinity of a valve 2). The diameter of the inner peripheral wall of the connector 8, in the area between connecting portions 9, 10 at the both ends, are larger by a predetermined value than the diameter of the inner peripheral wall of the standpipe 3, where the cushion material is fixed on and covers the inner wall of the connector 8, so that the whole inner surface in this larger-diameter space may serve as the pressure receiving surface. Further, with reference to the Official Gazette of Japanese Unexamined Patent Publication No. Hei 2-253099, the fluid hammer prevention device as disclosed in FIG. 17(B) shows an embodiment comprising a pressure absorbing body 2, a casing 3 and connectors 4, 5. The pressure absorbing body 2 comprises a cylindrical part 6 and an absorbing chamber 7 formed around the cylindrical part 6. The cylindrical part 6 is made of elastic rubber material, wherein a pressure wave absorbing channel is provided.
Each of the fluid hammer prevention devices discussed above is provided with the portion of larger inner diameter serving as the cushion chamber at an intermediate position of pipe, so that the cylindrical shape of cushion part may be fixed on the cushion chamber. However, since the subject fluid directly passes the pressure transmission passage penetrating through the center of the cushion part, the pressure fluctuation is directly supplied to the cushion part without passing any orifice, the corresponding larger volume of the cushion part according to such pressure fluctuation is required. Thus, the ordinary volume of the cushion part would be insufficient for showing the pressure fluctuation absorption effect.
On the other hand, with reference to the Official Gazette of Japanese Unexamined Patent Publication No. Hei 6-147391, the fluid hammer prevention device as disclosed in FIG. 17(C) shows an embodiment, wherein, a tube 30 made of elastic material such as rubber and serving as a second cylinder inside a cylindrical shape of case 3, is inserted and fitted in a space surrounded by an inner peripheral wall of the case 3 in the shape of cylindrical connector connected to an intermediate position of a pipe xe2x80x9caxe2x80x9d, and a sponge 31 occupies the space between the outer peripheral surface of the tube 30 and the inner peripheral surface of the case 3. When the pressure fluctuation is generated inside the pipe xe2x80x9caxe2x80x9d, the pressure fluctuation (pressure wave) may be absorbed while the tube 30 is expanded and presses the sponge 31 due to the generated pressure. According to this structure, although the good durability of cushion part may be expected because the sponge 31 made of elastic material is protected by the tube 30, the pressure fluctuation absorption effect would not be shown thoroughly, since the pressure fluctuation directly affects the cushion part via the tube 30 without passing any small holes, the corresponding larger volume of the cushion part according to such pressure fluctuation is required. Thus, the ordinary volume of the cushion part would provide the limited pressure fluctuation absorption effect, and the problem remains.
FIG. 17(D) of the present invention corresponds to FIG. 4(C) of the Official Gazette of Japanese Unexamined Utility Model Publication No. Hei 7-28296. This prior art is provided with numerous holes 53 on a pipe wall 52a, whereby the sufficient pressure fluctuation absorption effect may be obtained since the pressure fluctuation affects the cushion part filled with a compressive gas by passing through the orifice part. There are several problems, however, in regard to the durability such as that the compressive gas filled in the cushion part chronically goes out through the cushion wall.
The preferable in-line type fluid hammer prevention device would comprise, small holes leading to the fluid channel, a cylindrical diaphragm facing to the small holes with having a space between the diaphragm and the holes, and a cushion material provided around the outer periphery of the cylindrical diaphragm. When this type of fluid hammer prevention device is to be adopted, it is most important how this structure can be accomplished by simple assembly with least cost, at the same time, maintaining the pressure energy conversion efficiency of the cushion part for a long period of time.
The inventors focused on the problems arisen from the conventional type of fluid hammer prevention device as discussed above, and it is an object of the present invention to provide a compact in-line type fluid hammer prevention device, which maintains the superior pressure energy conversion efficiency for a long period of time by securing the fluid sealing tightness by means of the cylindrical diaphragm, and also shows improved pressure fluctuation absorption effect and/or the pressure energy conversion efficiency, by combining small holes leading to the fluid channel, a cylindrical diaphragm facing to the small holes with having a space between the diaphragm and the holes, and a cushion material provided around the outer periphery of the cylindrical diaphragm.
To achieve the objects mentioned above, according to claim 1 of the present invention, there is provided an in-line type fluid hammer prevention device, comprising an inlet cylindrical connecting body and an outlet connecting body connected at an intermediate position of the piping system in series forming a cylindrical space between the inlet cylindrical connecting body and the outlet connecting body. The inlet cylindrical connecting body and the said outlet connecting body are respectively formed a recessed seat facing to each other, each of the recessed seat is provided with a center through-hole at the center position connecting to a fluid channel inside the said pipe. Each end of a cylindrical shape sleeve is positioned at a space between the center through-holes of the inlet cylindrical connecting body and the outlet connecting body. A pair of protrusive flanges is protrusively formed from the sleeve to create gaps between the protrusive flanges and the recessed seats respectively. A cylindrical diaphragm having an elastic characteristic is positioned at an outer periphery of the said sleeve, and the pair of inward lip portions at each end of the cylindrical diaphragm are pressed and supported by the pairs of recessed seats and the protrusive flanges. There is formed a cylindrical chamber between the sleeve and the said cylindrical diaphragm, and the cylindrical chamber is connected to the fluid passage hole inside of the sleeve via a small holes on the wall of the sleeve, and the elastic cushion is placed at the outer periphery of the cylindrical diaphragm.
There is provided an in-line type fluid hammer prevention device comprising an inlet cylindrical connecting body and an outlet connecting body connected at an intermediate position of the piping system in series forming a cylindrical space between the inlet cylindrical connecting body and the outlet connecting body. The inlet cylindrical connecting body and the said outlet connecting body are respectively formed a recessed spherical seat facing to each other, each of the recessed spherical seat is provided with a center through-hole at the center position connecting to a fluid channel inside the said pipe. Each end of a cylindrical shape sleeve is positioned at a space between the center through-holes of the inlet cylindrical connecting body and the outlet connecting body. A pair of protrusive spherical flanges is protrusively formed from the sleeve to create gaps between the protrusive spherical flanges and the recessed spherical seats respectively. A cylindrical diaphragm having an elastic characteristic is positioned at an outer periphery of the said sleeve, and the pair of inward lip portions at each end of the cylindrical diaphragm are pressed and supported by the pairs of recessed spherical seats and the protrusive spherical flanges. There is formed a cylindrical chamber between the sleeve and the said cylindrical diaphragm, and the cylindrical chamber is connected to the fluid passage hole inside of the sleeve via a small holes on the wall of the sleeve, and the elastic cushion is placed at the outer periphery of the cylindrical diaphragm.
The radius of curvature of the recessed spherical seats formed on the inlet cylindrical connecting body and the outlet connecting body is larger than the radius of curvature of outer periphery of the inward lip portions formed at the both end of the cylindrical diaphragm.
The shapes of the recessed seats are multiple angled surfaces protruding toward and recessed from the cylindrical diaphragm, combined with the inward lip portions at the both end of the cylindrical diaphragm having much thicker than the thickness of the mid part of the diaphragm.
The shapes of the recessed seats are right angled protruding toward the cylindrical diaphragm and making gaps showing cranked shape between the recessed seats and the sleeve, combined with the lip portions at the both end of the cylindrical diaphragm having cranked shape being depressed toward the inner edge of spherical flange of the sleeve.
The elastic cushion is made of syntactic foam prepared by adding micro elastic balloon fillers to a base material made of gel or rubber.
And, the elastic cushion is made of foamed material of which initial hardness falls under the range of xe2x80x9cAsker C 30 and 85xe2x80x9d according to Japanese Industrial Standard S 6050 measured by the level gauge of a durometer xe2x80x9cAsker Cxe2x80x9d manufactured by Kobunshi Keiki Co., Ltd. of Kyoto, Japan, and of which apparent specific gravity falls under the range of 0.30 and 0.70.
With this structure, the inlet cylindrical connecting body and the outlet connecting body are connected at an intermediate position of the piping system in series. There are center through-holes provided at the center positions of both the inlet cylindrical connecting body and outlet connecting body, therefore the fluid flows through the in-line type fluid hammer prevention device. The both ends of the sleeve are positioned in the center through-holes facing to each other, thereof the cylindrical diaphragm is placed around the sleeve. The inward lip portions formed at the end of the cylindrical diaphragm are pressed and held by the protrusive flanges formed at the vicinity of the end parts of the sleeve, against the recessed seats of the inlet and outlet connecting body while assembling, and secure the water tightness of the elastic cushion. Accordingly, the fluid entering the center through-hole completely moves to the fluid passage inside of the sleeve without leaking out of cylindrical diaphragm. It is commonly known that the energy conversion efficiency of elastic cushion is in proportion to the displacement amount of the elastic cushion and to the inner friction effect, and when the elastic cushion is placed in the fluid channel, the fluid will go around the all surface of the elastic cushion in a short time, thus the elastic cushion is seen as if it were placed in the fluid. In this case, since fluid has the even pressure transmission characteristic, the energy scatter effect would occur. Eventually the pressure energy might be supplied evenly to every surface of the elastic cushion, thus it would be impossible to obtain the sufficient displacement amount and the inner friction effect necessary for the effective energy conversion. Therefore, as it is clear that the effective energy conversion may be done by small volume elastic cushion under the method of concentrated pressure energy in one direction by not scattering such pressure energy, the pressure energy conversion effect may be maintained for a long period of time by securing the water tightness of the elastic cushion by means of cylindrical diaphragm against the fluid.
As the fluid passage hole of the sleeve and the cylindrical chamber inside the cylindrical diaphragm are connected to each other via small holes provided on the wall of the sleeve, upon the occurrence of pressure fluctuation, first, the pressure energy is partially reduced when passing through the small holes, and further moves outwardly in the circumferential direction, and eventually reaches the cylindrical chamber inside the cylindrical diaphragm. The pressure energy is first reduced by these small holes, and is then transmitted to the elastic cushion via the cylindrical diaphragm. The cylindrical diaphragm will resist against the pressure energy, but expand, and the elastic cushion will also resist against the pressure energy, but is compressed and deformed, therefore, the complex energy conversion including all of the above with the sufficient displacement amount and the inner friction of the elastic cushion will be carried out at the same time.
The spherical surfaces have been formed by the recessed seat formed on the inlet cylindrical connecting body and the outlet connecting body, and by the protrusive spherical flanges protrusively formed at the both ends of the sleeve. When the inlet cylindrical connecting body and the outlet connecting body are assembled with the cylindrical diaphragm and the sleeve its inside, the outer surfaces at the end of the cylindrical diaphragm: formed in accordance with the shape of the inward lip portions are respectively become contact and compressed by the spherical flange of the sleeve against the part of the curved surfaces formed on the inlet cylindrical connecting body and the outlet connecting body, thus the fluid sealing tightness may be secured.
The radius of curvature of the recessed seats formed on the inlet cylindrical connecting body and the outlet connecting body is larger than the radius of curvature of the outer periphery of the inward lip portions formed at the both end of the cylindrical diaphragm. When the inlet cylindrical connecting body and the outlet connecting body are assembled, with the cylindrical diaphragm and the sleeve its inside, the outer surfaces at the end of the cylindrical diaphragm formed in accordance with the shape of the inward lip portions are respectively become contact and compressed by the spherical flange of the sleeve against the part of the curved surfaces formed on the inlet cylindrical connecting body and the outlet connecting body, thus the high fluid sealing tightness may be secured. Further, according to this relation of radius of curvature, while the cylindrical diaphragm repeatedly expands outwardly and retracts inwardly following to the compression and the reacted elasticity of the elastic cushion against the pressure fluctuation is applied to, there will be less possibility of the end portions of the cylindrical diaphragm at the outer periphery of the inward lip portions being worn due to abrasion against the recessed seats formed on the inlet cylindrical connecting body and the outlet connecting body, thus the durability as well as the high fluid sealing tightness against elastic cushion may be secured and maintained for a long time.
The shape of recessed seats formed on the inlet cylindrical connecting body and the outlet connecting body are an multiple angled surfaces protruding toward and recessed from the cylindrical diaphragm, combined with the inward lip portions at the both end of the cylindrical diaphragm having much thicker than the thickness of the mid part of the diaphragm. When the inlet cylindrical connecting body and the outlet connecting body are assembled, with the cylindrical diaphragm and the sleeve its inside, the outer surfaces at the end of the cylindrical diaphragm formed in accordance with the shape of the inward lip portions are respectively become contact and compressed by the spherical flange of the sleeve against the multiple angled surfaces formed on the inlet cylindrical connecting body and the outlet connecting body, thus the high fluid sealing tightness may be secured. In particular, when the cylindrical diaphragm is pressed against multiple angled surfaces of the inlet and outlet connecting bodies, the press margins on the outer surfaces at the end portions of the cylindrical diaphragm are depressed and deformed to fit tightly creating higher and intense contact pressure, thus the fluid sealing tightness will further improve.
The shapes of the recessed seats are right angled protruding toward the cylindrical diaphragm and making gaps showing cranked shape between the recessed seats and the sleeve, combined with the lip portions at the both end of the cylindrical diaphragm having cranked shape being depressed toward the inner edge of spherical flange of the sleeve. When the inlet cylindrical connecting body and the outlet connecting body are assembled, with the cylindrical diaphragm and the sleeve its inside, the outer surfaces at the end of the cylindrical diaphragm formed in accordance with the shape of the inward lip portions are respectively become contact and compressed by the spherical flange of the sleeve against the cranked shape surfaces formed on the inlet cylindrical connecting body and the outlet connecting body, thus the high fluid sealing tightness may be secured.
Since the elastic cushion is made of the syntactic foam prepared by adding elastic micro balloon fillers to a base material such as gel or rubber, and is protected by the cylindrical diaphragm having the elastic characteristic, the excellent pressure fluctuation absorption function may be expressed, and the pressure energy conversion efficiency may be maintained for a long period of time.
Further, since the elastic cushion is made of the foamed material having the initial hardness of xe2x80x9cAsker C 30-85xe2x80x9d and the apparent specific gravity of 0.30-0.70, and is protected by the cylindrical diaphragm having the elastic characteristic, the excellent pressure fluctuation absorption function may be expressed, and the pressure energy conversion efficiency may be maintained for a long period of time.